Process for refining hydrocarbon oils



y 14, 1940- E. R. P. E. RETA'lLLlAU 2.200304 PROCESS FOR REFININGHYDROCARBON OILS Filed May 18, 1938 Dilure Suhonic Acid DisrillcneVapors: 5]

lnvenror: Edmond By his Arrorneg= P. E Reroilliau Patented May 14, 1940PATENT crater 2,200,704 PROCESS roe REFINING HYDROOARBON OILS Edmond R.P. E. Retailliau, Edwardsville, Ill., as-

signor to Shell Development Company, San Francisco, Calif., acorporation ofDelaware Application May 18, 1938, Serial No. 208,698 1Claims. (01. 196-'-36) a This invention relates to a process for refining hydrocarbon oils in a heated vaporous condition by contactingsame with a chemically acting acid refining agent, and more particularly is concerned with the vapor phase refining of gasoline distillates'atelevated temperatures wit dilute solutions of organicsulfonic acids.

The use of organic sulfonic acids in the vapor phase treatment ofhydrocarbon distillates has t been described in the Moser Patent No.2,055,416, according to which sulfonic acids are dissolved in a liquidorganic solvent such as a mineral oil substantially non-volatile underthe conditions of the treatment. The distillate vapors and the solutionof sulfonic acid are suitably contacted,

whereby a portion of the sulfonic acid in the solution is spent andvapors are refined. Thetreated vapors are separated from the solutionand are condensed. added to the solution to replace the spent POT", tionand the. resulting regenerated solution is used for treating furtheramounts of the dis-' tillate vapors.

I have found that the above method entails .25 considerabledifiiculties, one of the most serious being the gum and coke formationin the solution, thesulfonic acids slowly attacking the oil (solvent,thereby being consumed and forming undesirable by-products which tend togum and coke up the equipment.

It is a purpose of this invention to provide a method for refiningunstable hydrocarbon distillates, such as cracked gasoline distillatesto produce stable oils of good color and color stabil- =35 ity, low gumand high guminhibitor susceptibility. It is another purpose to achievethis result by treating same with organic sulfonic acids underconditionsto avoid gumming and coking of the equipment. It is another purposetocarry 40 out theprocess so that a minimum of organic sulfonic acid isexpended anda minimum loss of hydrocarbon distillate is sustained; andit is another; purpose to eliminate recirculation of unconsumed treatingreagent thereby material- 45 ly simplifying the refining equipment.

I have discoveredthat hydrocarbon distillates can be treated effectivelywith organic monoand. poly-sulfonic acids to the exclusion of thedifficulties hereinbefore described if the sulfiLO fonic acids areinjected into the hydrocarbon [,vapors in amounts. which are completelycon sumed in a oncethrough operation, provided suf-.

ficient time of contact is allowed, in the form ,of dilute aqueoussolutions. My method con- .55 sists essentially of introducing the exactamount Fresh sulfonic acid is,

of sulfonic acid which is required to, refine a given hydrocarbon oil toa desired degree and which is completely converted to sludge in a singlecontact, inthe form of a dilute solution, preferably aqueous solution,of less than about concentration into the hydrocarbon vapors and passingvapor and reagentas a mixture through a treating zone containing solidob structions, for instance in the form of a packing. After passingthroughthe treating zone, refined hydrocarbon vapors and resultingsludge are separately withdrawn and vapors are condensed. The resultingcondensate is normally neutral and may be sweetened by any conventionalsweetening process. At times it may contain small amounts of S02liberated from the sludge by thermaldecomposition, in which case it mustbe neutralized.

Oils susceptible to my treatment are in par ticular cracked gasolinedistillates, although the 120 process is applicable as well to crackedtractor fuels having boiling ranges from about 200 up to about 575 F.,and distillate fuel oils such as the No. 1 to No. 3 fuel oils by theA.S. T. M. specifications D396-34T, which oils may boil between about 300to 600 F. ;A common diificulty of burnersdesigned to operate ondistilled fuel oils is the clogging of the screen through which the fuelmust pass before combustion. This clifiiculty islargely overcome whentreating the distillate fuel oils by myprocess. Moreover as the resultof the treatment carbon forming bodies which have a tendency to causesoot are at least partially eliminated.

Frequently a considerable desulfurization is noted in particular whenoperating on high sulfur distillates; and nitrogen bases contained inthe distillates may be and usually are completely removed in the courseof my treatment.

sulfonic acids to be suitable for my process should preferably be atleast slightly soluble in .of phenols and cresylic acids, etc. Alsomixtures of different sulfonic acids are often very useful, and thesulfonic acids may contain varying amounts of sulfuric acid, sulfuricacid in accordance with my co-pending application Serial No. 208,697,filed May'18, 1935, being a use ful treating reagent under theconditions of my process. On the other hand, metal salts of sulfonicacids are substantially ineffective in my process, the refining effectof salts such as zinc and other metal sulfonates being too weak un derthe conditions of my process and having the disadvantage of tending toplug the treating zone. To providean effective contact between thesolution of the reagent and the vapors, the former is effectivelydispersed within the latter as by spraying, spreading over a largecontact surface such as that of a packing, or other suitable means. Thevolume ratio of the reagent solution to hydrocarbon vapors being verysmall in my process in spiteof the-'highdegree of dilution of theformer, treatment by passing the vapors through a liquid pool of'thesolution is impractical, if not impossible; T

Thetreating zone may conveniently consist of a vertical tower or columncontaining an inert relatively coarse packing such as broken brick,

.tile, pumice, coke, steel wool, rings made from silicious materials,iron'copper, etc.. In general it is unnecessary that the packing becorrosion resistant against the sulfonic acid, because with- .in a shorttime it is completely covered by a protective coating of sludge. It is,however, nec essary that the packing material be inert towards thesludge, and it should preferably'have a compressive strength sufilcientto support a bed at least 20 to 40 feet deep, even after prolongedexposure to the sludge.

During the contact of the reagent solution and hot hydrocarbon vapors,several reactions take place almost simultaneously. Water of solutionbegins to vaporize immediately, whereby the reagent within theindividual droplets or. the film is concentrated rapidly. Simultaneouslythe sulfonic acid begins to react with the most reactive components inthe vapors. The result is that by the time the reagent has beenconcentrated. toa point sufficient to cause charring or oxidation,

which it can be withdrawn readily. In the early stages of its formationthis sludgeexerts a definite refining action on partly refined vaporsuntil its free acidity is substantially consumed or the vapors becomeunreactive. The final: sludge differs considerably from acid sludgesformed in conventional sulfonic acid treatment. For instance, itcontains no free sulfonic acid and is substantially non-corrosive toiron, copper and many other metals. It has a pleasant aromatic odor, iscompletely soluble in gasoline, insoluble in water and ethyl alcohol,and does not usually evolve S02 on standing at room temperature. Itssulfur content is high and hydrolysis with a concentrated HCl at 300 F.under reflux has shown it to be free from esters.

The reagent solution and vapors may be passed through the treatingzoneconcurrently or countercurrently. In general I prefer concurrent flow,as it normally results in smaller treating losses for a given degree ofstabilization of the hydrocarbon oil. This may be due to the fact thatin concurrent flow the most reactive and most unstable components of thehydrocarbon vapors are removed by the fresh reagent. If the correctamount of the reagent is used, i. e., that which is substantially spentand used upwhen the most unstable components have been converted tosludge and/or polymers, other com-' ponents which are more stable andyet capable of reacting with the reagent are but little affooted,because the reaction which they undergo in contact with sludge in thedigesting period following the first rapid reaction, appears to be ofthe nature of reforming resulting in little addi tional formation ofsludge and polymers, if any,

but usually resulting in a considerable increase in stability, guminhibitor susceptibility and other properties of the distillate whichdepend upon which at least a portion of the most reactive componentshave already been eliminated in the form of sludge and high boilingpolymers. Conse quently, the more stable reactive components will beattacked to form additional sludge and high boiling polymers.

As hereinbefore stated I use an amount of treating reagent which iscompletely usedup in a single pass. This has the advantage in additionto forming a non-corrosive sludge, of obviating recirculation ofunconsumed reagent, a"

feature which greatly simplifies the treating equipment and reduces thecost of installation. Moreover, at no time are vapors exposed to anexcess of reagent, so that only the very minimum amount of reagent isconsumed and onlythe most unstable components are converted to yield theminimum amount of sludge and polymers.

, The distillates resulting from my treatment are improved in regard totheir color, gum stability, susceptibility toward gum inhibitors, as

is usual in chemical refining processes. In one important aspect,however, the distillates from my process differ from those of othersulfonic acid treatingprocesses. Normally sulfonic acid treatmentmaterially reduces the octane number of gasolines. My treatment,however, normally does not affect the octane number and in someinstances an appreciable rise has been noted;

Small amounts of the polymers formedbymy treatment retained by or addedto treated disfluences the efiectiveness of distribution of the reagentthroughout the vapors, and, if too high, may be the, cause of charring,burning and/or oxidation of the vapors. The greater the dilution, thegreater is the volume of treating solution to be used and the moreefficiently can it be injected into and distributed throughout thevapors. From this point of view it is in general desirable to useconcentrations not in excess of about 10% by weight, although whenoperating at relatively low temperatures, concentrations up to about 20%by weight, may be employed without substantial danger of charring andburning. On the other hand at relatively high temperatures I havesuccessfully used solutions having concentrations as low as .5% and evenlower concentrations may be employed, if desired.

Amounts of reagents suitable for my treatment are between. about .02 to4 lbs. and preferably less than about 1 lb. of reagent per barrel ofdistillate. To minimize consumption of reagent, the minimum amount whichgives a satisfactory treating result is obviously the most desirable.

This minimum varies considerably with thetype of distillate undertreatment .and also with the individual sulfonic acid used.

Suitable contact temperatures are in general of the order of about 200to400 F., temperatures between about 230 to 300 F. being preferred. Atrelatively high temperatures i.'e., 300 Rand higher, the sludge has aconsiderable tendency to decompose, thereby liberating S02 and formingcoke, and at temperatures below about 250 F. av erageugasolinedistillates are incompletely vaporized. If relatively low temperaturesare desired, resort may behad to subatmospheric pressures in order toeffect complete vaporization. It is desirable that the hydrocarbondistillate be completely vaporized in the treating zone, as I have foundthat the presence of hydrocarbons in the liquid state adversely affectsthe treating results and in particular raises the polymerization losses.

Superatmospheric pressures may be employed if desired but are limited byconsiderations of temperatures and volatility of the hydrocarbons asexplained above. The effect of sup-eratmospheric pressures is mainlythat of lengthening the time of contact in the treating zone for a giventhroughput and also of reducing the hypothetical potential concentrationof the reagent at a given temperature, due to an increase of the steampressure in the vapors. On the other hand when treating relatively highboiling distillates a. considerable vacuum may have to be maintained inthe treating zone to enable substantially com plete vaporization and toprevent condensation of the distillate at the most desirable treatingtemperatures.

The time of contact may be varied between the limits of about 3 to 90seconds and may if desired beextended beyond these limits. In general atrelatively low temperatures longer times of contact are permissible andrequired than at higher temperatures under otherwise equal conditions.Reaction times of less than about 3 seconds are normally insufiicient.With increasing time of contact above about 3 seconds the stability ofthe hydrocarbon oil increases while treating losses may rise but littleand often remain substantially unchanged. On the other hand if contactis extended beyond a certain time which depends largely upon thetemperature, stability is not further improved materially and certaindisadvantages make themselves felt such as the extremely.

large size of the reaction vessel which is required fora giventhroughput and the great tendency oi the sludge to decomposetherebyliberating SO:

which is harmful to the gasoline, and coke which is liable to plug thepacking.

Coking of the sludge can be minimized within limits by employingmulti-stage treating systems in which the treating reagent is dividedinto as many portions as there are stages, one portion being injectedinto each stage, sludge being withdrawn separately from each stage, andthe vapors are passed serially through the several stages. Theconcentration of the solutions injected into the several stages need notbe the same, neither is it necessary to maintain the same treatingconditions in the various stages. On the contrary, Ihave found that itis advantageous to maintain progressively lower temperatures between 200and 400 F. in successive stages, and to inject aqueous reagent solutionsof progressively higher concentrations.

As to the amount of sludge formed in the several stages I have foundthat most of it is produced in the first stage, very little if any beingformed in subsequent stages.

It is usually unnecessary, though permissible, to precede my treatmentwith a caustic alkali or an acid wash for the removal of impurities suchas mercaptans, alkyl phenols, nitrogen bases, etc. A preliminary liquidphase wash has the disadvantage of necessitating the steps of condensingand redistilling the treating stock, whereas in the absence of such awash these steps are obviated.

My process will be further understood from the drawing which representsa simplified flow diagram of one form ofmy process.

A dilute aqueous solution of a suitable reagent, such as benzenesulfonic acid is admitted to the top of treating tower I through line 3,and a similar solution may be injected into the top of treating tower 2through line 4 from sources not shown. Distillate vapors of the propertemperature enter tower I near its top through line 5, or near itsbottom through line 6. In the tower the acid and the vapors are closelycontacted and re act as hereinbefore described, forming a fluid sludgewhich is withdrawn through bottom line I. If the vapors are admitted atthe top they are withdrawn near the bottom through line 8 at a pointsufliciently above the sludge line I to permit a clean separation ofsludge and vapors. The treated vapors may be passed through line 9directly to condenser III, in case tower I only is in operation. If bothtowers I and 2 are in use, the vapors may pass through reheater II inline I2 which serves to readjust the temperature and the reheated vaporsenter tower 2 near its top. If desired the reheater II may be by-passedthrough line 2|. The vapors in tower 2 in contact with the sulfonic acidsolutionfrom line 4 produce a small amount of sludge which is removedthrough bottom line I3 and is collected in tank I4 together with sludgefrom tower I and line I. Vapors treated in tower 2 leave through line I5near the bottom and pass through line 9 to condenser II! where they arecondensed, condensate being accumulated in tank I6.

A similarprocedure applies, if the raw distillate vapors enter tower Ithrough line 6 near its bot tom. Treated vapors are withdrawn throughtop line I! and may pass tocondenser II), or they may go to the bottomof tower 2 through reheater l9 situated in line H3 or by-pass 22, to befurther treated. Retreated vapors leave tower 2 through top line 20passing to condenser I0 and tank I6. In some cases it may beadvantageous to use concurrent flow in treater. I and countercurrent iniii:

treater 2 or vice versa, depending on the refractoriness of thecharging, stock.

Steam may be injected into towers l and/or 2 if desired through lines 23and/or 24 respectively, at some convenient points to facilitate thevaporization of the distillate.

The following examples further serve to illustrate my process:

Example I A highly unstable cracked gasoline distillate was washed withdilute aqueous solutions of canstic soda and sulfuric acid at aboutnormal room temperature, and the washed distillate was refined byconcurrently contacting same in the vapor phase at 280 F. with a 2%solution of benzene sulfonic acid in water, in an amount of 30% byvolume of the gasoline (equal to 2.1 lbs. benzene sulfonic acid perbarrel of the gasoline). The contact time was varied from 3.6 to 14.6seconds with the following results:

Treating time 6 7. 3 l3 l4. 6 Polymerization loss 1. 4 l. 4 2.2 2. 3Sludge loss .8 .8 .8 .4 Recovered gasoline 97.8 97.8 97 0 07.3 Inductionperiod of sweetened gasoline,

hours 1 2% 4 4% Ditto, plus 001% gum inhibitor 2% 5 6+ 7% Example II Inanother series of tests, a cracked washed gasoline similar to that of'Example I was contacted concurrently in the vapor phase with an 8.3%solution of benzene sulfonic acid in an amount of 3% by volume ofthe'gasoline (equal to .083 lb. benzene sulfonic acid per barrel ofgasoline) for 4.1 seconds at various temperatures. The treating resultswere as follows:

Treating temperature, F 230 265 280 305 Polymerization loss *1. 8 0.0 9.3 Sludge loss 6 6 .3 3 Recovered gasoline 97 0 99. 4 98. 8 99. 4Properties of gasoline after doctor sweeten- Induction period, hrs $4 1%3% 3% Color Saybolt l8 l8 l8 18 A. S. T. M. gum 0 .1 2 Octane number 68%68 *Gcsoline was partially in liquid phase. The octane number of thepretreated charging stool: was 65.

The efiect of the presence of liquid gasoline during treating on thepolymerization loss, and the unfavorable influence of the temperatureabove 300 F. on the gum content are to be noted.

Example III The influence of the quantity of refining reagent wasdetermined in another series of tests in which a pretreated gasoline,similar to those of the previous example, was concurrently treated inthe vapor phase at 280 F. for about 14 seconds with varying amounts ofbenzene sulfonic acid dissolved in water to form dilute solutions.

Acid consumption, lbs. per barrel .091 52 .88 2.1 Polymerization loss 1.7 2. 2 l. 5 2. 1 Induction period, hrs., sweetened with silver nitrate 53% 4 Ditto, plus 001% gum inhibitor 6% 5+ 6% .6+

As will be noted, equally good results are obtained with widely varyingamounts of the refining reagent.

Example IV A caustic soda and dilute sulfuric acid washed crackedgasoline distillate similar to those used in the previous exampleshaving anoctane number of 67 .5 was treated in two stages at 300 F. with.4 lb. per barrel of benzenev sulfonic acid in each stage. The acid wasinjected into the vapors in the form of a .75% aqueous solution in thefirst stage and a 3.0% aqueous solution in the second stage. The totaltime of contact was 60 seconds. Treating results were as follows:

Treating loss percent 3. Induction period after sweetening hou.rs 5Inhibitor susceptibility for U. 0. P. inhibitor No. 2 240 Octane number68 Inhibitor susceptibility as herein defined is the increase in minutesof the induction period upon addition of 1 mg. inhibitor per 100 ml.gasoline.

When treating the above washed cracked gasoline with 1 lb. per barrel ofconcentrated sulfuric acid in the conventional manner at ordinary roomtemperature, a loss of the same magnitude was sustained and theinhibitor susceptibility for the same inhibitor was 80.

Example V Cracked gasoline distillate, prewashed at normal roomtemperature with dilute aqueous sulfuric acid and caustic sodasolutions, was treated in the vapor phase with varying amounts ofbenzene sulfonic acid containing 20% sulfuric acid, the acid mixturebeing introduced in the form of a 1% aqueous solution. The vapors andtreating solution were passed in concurrent flow through the treatingzone containing a packing maintained at a temperature of 280 F. The timeof contact was 20 seconds. Results were as follows:

. 08 46 Color Saybolt 28 28 30+ 30+ Copper dish gum. 3 4 0 iLdS. M.gnuiln 1 /6 .3 0 n no ion perlo 4 l 2 2 l Inhibitor susceptibility (U.0. P

i No. 2) 180 300 Sulfur reduction, percent 20 33 Example VIConcentration of solution, percent Amount of acid used lbs./bbl ColorSaybolt Copper dish gum.

Induction period Gum inhibitor suscept It will be noted that the moredilute solution resulted in a somewhat superior gasoline in spite of thesmaller amount of acid used. Moreover it was possible to continue thetreatment with the 1% solution indefinitely without clogging thereaction zone, whereas when using the 75% acid the packing in thetreating zone was choked with carbonaceous matter within a few hours.

I zone containing a packing of, carbon rings. The

time of contact was,20 seconds at 280 F, Re-

timate contact through a reaction zone at a temperature between 200 and400 F., said amount and concentration being so chosen to preventsubstantial condensation of the vapors, maintaining saidcontact foratime suflicient to vaporize water ofsolution, thereby concentrating thereagent simultaneously to react at least a portion of said unstablecomponents with the reagent,

whereby a sludge is produced, and separating sults were as follows: theresulting vapors from the sludge.-

2-4 dinitro p-Xylene 1-5 naphthol. I-naphthol Sul- Acid used sulfonicdisulfonic fi-sulfonic 1 535253 fanilic acid acid acid acid 301dAmount,;lbs./bbl .35 i .35 .35 .17 -.35 Properties of gasoline: 1

Color, Saybolt 30+ 30+ 30 30+ 30+ Copper dish gum 3 2. 5 6 5. 5 9 A. S.T. M. gumm. .2 .6 l. .8 0.0 Induction period..- 1% 2 1% 3 2 /4 Inhibitorsusceptibility 340 360 400 260 260 While in the foregoing I havedisclosed water only as a suitable solvent for sulfonic acids, I may useother solvents which are substantially chemically inert andsubstantially completely vaporizable under the conditions of thetreatment. For instance, when carrying out my treatment with oil solublepetroleum sulfonic acids such as are obtained in the treatment ofviscous petroleum oils with fuming sulfuric acidto produce medicinaloils I may dissolve these acids in pen tane, hexane, straight rungasoline, etc.

I claim as my invention:

1. In the process of removing gum forming components from hydrocarbonoil Vapors in a heated condition with a refining reagent, the improvement comprising injecting into said heated hydrocarbon vapors anamount of a dilute reagent solution having a concentration of .5 to 20%in a solvent which is chemically inert and substantially completelyvaporizes under the conditions of the treatment, said reagent consistingpredominantly of organic sulfonic acid, said amount being between .05and1 pound of said reagent per barrel of said oil and being completelyconsumed in a once-through operation under the conditions of thetreatment, conducting said va-.

pors and said sulfonic acid solution in intimate contact through areaction zoneat a temperature between 200 and 400 F., said amount andconcentration being so chosen to prevent substantial condensation of thevapors at the temperatures of the treatment, maintaining said contactfor atime sufficient to vaporize the solvent substantially completely,thereby concentrating the reagent simultaneously to react at least aportion of said gum forming components with the reagent whereby a sludgeis produced, and separating the resulting vapors from the sludge.

2. The process of claim 1 in which a subatmospheric pressure ismaintained in the reaction zone.

3. In the process of removing gum forming components from hydrocarbonoil vapors in a heated condition with a refining reagent, theimprovement comprising injecting into said heated hydrocarbon vapors anaqueous solution having a concentration of .5 to 20% of a reagentconsisting predominantly of organic sulfonic acid in an amount between.05 and 1 pound of said re- 4. In the process of removing gum formingcomponents from hydrocarbon oil vapors in a heated condition with arefining reagent, the improvement comprising injecting into said heatedhydrocarbon vapors an amount of a dilute reagent solution'having aconcentration of .5 to 20% in a solvent which is chemically inert andsubstantially completely vaporizes under the conditions of thetreatment, said reagent consisting predominantly of organic sulfonicacid, said amount being between05 and 1 pound of said reagent per barrelof said oil and being completely consumed in a once-through operationunder the conditions of the treatment, conducting said vapors and saidsulfonic acid solution in intimate contact through a reaction zone at atemperature between 200 and 400 F'., said amount and concentration beingso chosen to prevent substantial condensation of the vapors at thetemperatures of the treatment, maintaining said contact for a timesuiliicient to vaporize the solvent substantially completely, therebyconcentrating the reagent while reacting a portion of said unstablecomponents with the reagent, whereby asludge is produced, and extendingthe contact between the unreacted vapors and the sludge sufficiently toconvert at least a portion of remaining unstable components to morestable products, and separating the resulting vapors from the sludge.

5. In the process of removing gum forming components from hydrocarbonoil vapors in a heated condition with a refining reagent, theimprovement comprising passing said heated hydrocarbon vapors seriallythrough several reaction zones, injecting into each zone aqueoussolutions having concentrations between .5 to

20% of reagents consisting predominantly of organic sulfonic acids inamounts between .05 and 1 pound of said reagents per barrel of said oil,said amounts of reagents being completely consumed ina once-throughoperation under the conditions of the treatment, providing for intimatecontact of said vapors and solutions in the several zones attemperatures between 200 and 400 F., said amounts and concentrationsbeing so chosen to prevent substantial condensation of the vapors,maintaining said contacts for periods of time suflicient to vaporize thewater of solution and to react at least a portion of said unstablecomponents with the sulfonic acids, whereby a sludge is produced andseparately removing sludge from each zone.

I 6 In the process of removing gum forr'nin'g' components fromhydrocarbon oil vapors in a heated condition with a refining reagent,the improvement comprising passing said heatedl hydrocarbon vaporsserially through several reaction zoneshaving progressively lowertempera tures between 200 and 400 F., injecting into the several zonesaqueous solutions having concentrations of .5 to 20% of reagentsconsisting predominantly of organic sulfonic acids, in amounts between.05 and 1 pound of said reagents per barrel of said oil, said amounts ofreagents being completely consumed in a once-through operation throughof the treatment, providing for an intimate contact in the several zonesunder conditions to prevent substantial condensation of the vapors,

said zones under the conditions i maintaining said con'ta'ctsforperiodsof time sufficient to vaporize the water of solution and to react atleast a portion of said unstable components with the sulfonic acids,whereby a sludge is produced, and separately removing sludge fromeachzone.

'7. The process of claim 1 in which the hydrocarbon vapors' areconducted through the reaction zone in concurrent flow.

s. The process of claim 1 in which the time of. 10 contact is sufiicientto produce a sludge substantially free of free acid. 7

9. The process of claim 3 in which the sulfonic acid is benzene sulfonicacid.

10. The process of claim. 47in. which the total time of contact isbetweenB and 90 seconds. EDMOND R. P. E. RETAIILIAUI

